Panel for forming a floor covering, method for manufacturing such panels and granulate applied herewith

ABSTRACT

Panel for forming a floor covering, wherein this panel comprises at least a layer of thermoplastic material, wherein said layer also comprises at least individual fibers having a length greater than 1 millimeter.

BACKGROUND OF THE INVENTION

1. Field of the invention

This invention relates to panels for forming a floor covering, to amethod for manufacturing such panels, and to a granulate appliedtherewith.

More particularly, the invention relates to panels comprising at least alayer, more particularly a substrate layer, of thermoplastic material.Further, such panels may also comprise, above said layer, at least a toplayer with a printed decor and a translucent or transparent wear layer.

In particular, the present invention relates to panels of the typewhich, on two or more opposite edges, comprises coupling means orcoupling parts with which two of such floor panels can be coupled atsaid edges in such a manner that they are mutually locked in ahorizontal direction perpendicular to the respective edge and in theplane of the floor panels, as well as in a vertical directionperpendicular to the plane of the floor panels. Such floor panels can beapplied for composing a so-called floating floor covering, wherein thefloor panels are connected to each other at their edges, however, liefreely on the underlying surface.

2. Related art

Such panels are known, for example, from EP 1 938 963, EP 2 339 092 A1and WO 2010/023042. From these documents, more particularly vinyl-basedfloor panels are known for forming a floating floor covering. Suchvinyl-based floor panels mostly have a thickness of 3 to 5 millimetersand have a high material density. The respective core of the panels iscomposed of one or more layers of thermoplastic material, for example,soft PVC, which can comprise fillers. Above the print, a transparentthermoplastic layer and possibly a superficial layer of lacquer areprovided. According to EP 2 339 092 A1, a reinforcing layer on the basisof glass fiber can be applied.

The panels of the state of the art show the disadvantage that they arestrongly subjected to shrinkage and expansion under the influence oftemperature. Shrinkage and expansion may lead to that the floor coveringor the individual panels are pushed upward, and, for example, to amutual release of the coupling parts, or to the phenomenon that theindividual panel-shaped elements will drift apart, whereby gaps mayoccur. The features of the panels of the state of the art are such thatproblems may occur already with warming due to incident sunlight, forexample, at a window in a room.

From WO 2012/004701, it is known to apply a glass fiber layer orembedded profiles for increasing the dimensional stability of suchpanels. In particular, here the bending stiffness of the panels has beentackled.

U.S. Pat. No. 6,306,318 describes a method for recycling discardedcarpets, wherein, starting from a molten mixture of a recyclate on thebasis of discarded carpets and fresh soft PVC, flexible floor tileshaving a minimum thickness of approximately 5 millimeters are producedby means of an injection molding process. The mixture comprises anamount of plasticizers of maximum 5 percent by weight. The obtainedfloor tiles have a uniform composition across their thickness andcomprise 10 to 20 percent by weight of unmelted carpet fibers ofpolyamide or polyester, which are distributed uniformly across thethickness of these tiles. The fibers provide for a wear-resistantsurface. As an alternative for the recyclate of discarded carpets, alsorecyclate of glass fiber-reinforced synthetic material (English:fiberglass) can be applied. In the case of carpet, it is started withcarpet fibers of approximately 3.2 millimeters or more, wherein areduction of the length during the process is avoided as much aspossible. However, it can be expected that disintegrating the carpetsand processing them in the extruder prior to injection molding in factwill lead to shortening the present fibers. It is unclear what thelength of the glass fibers will be when starting from a recyclate ofglass fiber-reinforced synthetic material. Further, it is unclear howmany glass fibers will have been incorporated into the matrix of thetile and which type of glass fiber is applied. The obtained tile isrelatively hard and the flexibility leaves much to be desired. This maylead to problems with the impact sound during use and an incapability ofadapting to unevennesses of the underlying surface. The injection-moldedtile comprises coupling means along the edges, however, these do notprovide for a locking in vertical direction. Moreover, the precision ofinjection molding, in particular in the case of soft thermoplasticmaterials, is inferior. This method is time-consuming, and moreoverthere is little possibility of variation in the appearance of the wearside of the tiles. Such tiles possibly still show a strong dimensionalchange with changing temperature.

GB 1 248 060 describes, as an alternative of a method similar to that ofU.S. Pat. No. 6,306,318, the possibility of manufacturing reinforcedthermoplastic materials by means of a method wherein continuous fiberlayers are stacked and pressed alternating with thermoplastic granulatelayers. In this manner, a disintegration of the present fibers in theextruder is avoided. According to the examples, hard PVC can be appliedas thermoplastic material.

SUMMARY OF THE INVENTION

The present invention relates to an alternative panel, which, in thefirst place, is intended as a floor panel for forming a floating floorcovering. According to various preferred embodiments of the invention,also a solution is offered for one or more problems with the panels ofthe state of the art.

To this aim, the invention, according to its first independent aspect,relates to a panel for forming a floor covering, wherein this panelcomprises at least a layer consisting of thermoplastic material, withthe characteristic that said layer also comprises individual fibers,preferably of a length greater than 1 mm. By “individual fibers”, it ismeant that they as such do not form part of a layer or a pre-fabricatedlayer, such as a glass fiber cloth, but rather, for example, aredistributed freely within the thermoplastic material, whether or notuniformly. The inventors have found that the use of such loose orindividual fibers can contribute to the dimensional stability of thepanels to a major extent, and then in particular can restrict the extentof expansion or shrinkage. Generally, such individual fibers seem betterembedded in the thermoplastic material than, for example, a glass fibercloth. Moreover, they can be active over a greater thickness of thethermoplastic material than such glass fiber fleece (non-woven) or glassfiber cloth (woven), such that shrinkage or expansion by shifting awayover such glass fiber cloth largely can be prevented.

Preferably, the respective fibers have an average length of 3millimeters or more. Good results have been obtained with fibers havingan average length of approximately 4.5 millimeters. Preferably, theaverage length is shorter than 10 millimeters or even shorter than 6millimeters.

Preferably, the respective layer comprises between 1 and 25 percent byweight of the respective fibers, and still better between 5 and 15percent by weight, without including possible other fillers, such aschalk.

Preferably, glass fibers are applied for the fibers. Preferably, E-Glassis chosen, for example, as defined in DIN 1259. According to analternative, steel fibers or other fibers, such as carbon fibers, aramidfibers or polyethylene fibers can be applied.

Preferably, moisture-resistant fibers are applied and, thus, nocellulose fibers, unless they are coated or treated, for example, bymeans of acetylation, in order to render them, at least to a certainextent, moisture-resistant.

Preferably, the fibers, for example, glass fibers, on average have adiameter situated between 1 and 100 micrometers or still better between3 and 30 micrometers, wherein in various experiments the range between 5and 25 micrometers has proven to be the best.

Preferably, the fibers are provided with a coating or a treatment whichimproves the adherence to the thermoplastic material. Preferably, thesurface of the fibers is treated with a coupling agent, such as withsilane.

Preferably, the fibers have a thermal expansion coefficient which issmaller than that of the thermoplastic material in which they aresituated, and/or a Young's modulus which is higher than that of thethermoplastic material in which they are situated.

Preferably, fibers are applied having a Young's modulus of more than 40,still better of more than 60 GPa.

Preferably, fibers are applied having a thermal expansion coefficient ofless than 30 μm/mK and still better of less than 5 μm/mK.

Preferably, said thermoplastic material relates to polyvinyl chloride,preferably semi-rigid or even soft polyvinyl chloride (PVC), namely PVCwith plasticizers, for example, with a percentage of plasticizers in thePVC of more than 20 or more than 30 percent by weight. It is clear thatinstead of using PVC, it is also possible to apply polypropylene (PP),polyethylene (PET) or polyurethane (PUR).

Preferably, the panel of the invention also comprises, above said layer,at least a printed decor and a translucent or transparent wear layerprovided there above. Said decor can consist of a print performed on asynthetic material film, for example, a printed PVC film, PU film, PPfilm, PET film. In the case of a PP film, this may relate, for example,to oriented polypropylene films. The wear layer preferably alsocomprises a thermoplastic material, such as PVC, PU, PP or PET.Preferably, the transparent thermoplastic wear layer is free from solidadditives, such as ceramic particles for enhancing wear resistance,although this kind of particles as such is not excluded. However, theinventor has found that they can be omitted with the aim of obtaininggood transparency while still maintaining an acceptable wear resistance,namely a wear resistance comparable to or better than that of a laminatepanel of the AC2 or AC3 class, as measured according to EN 13329. Thewear layer preferably has a thickness of minimum 0.15 millimeters andstill better minimum 0.3 millimeters, however, preferably less than 1millimeter, wherein 0.2 to 0.4 millimeters is a good value. With thisgood value, by means of the thermoplastic material of the wear layeralone, thus, without taking into account possible solid additives,already a sufficient wear resistance can be obtained for residentialapplication. So, for example, it is possible to achieve an IP value(initial wear point) of 2000 or more in the Taber tests, as described inEN 13329, annex E.

According to an alternative, it is not excluded that the printed decoror the print might be provided on the underside of the wear layer.

Preferably, said thermoplastic layer also comprises at least a glassfiber cloth or glass fiber fleece. Preferably, this here relates to aso-called “non-woven”, namely, a glass fiber fleece. The inventors havefound that with a glass fiber fleece, better embedding in thethermoplastic material can be obtained and therefore a more efficientworking of the glass fibers.

Preferably, the thermoplastic layer, which, according to the invention,comprises the individual fibers, relates to a substrate layer, namely alayer which extends underneath a top layer. Preferably, such layer issituated at least halfway in the thickness of the panels. In thismanner, the risk of a possible bending effect with changing temperatureis restricted or excluded.

The substrate of the panel can be composed in various possible manners.Below, some possibilities are summed up, without being exhaustive.

According to a first possibility, the panel comprises at least two suchlayers on the basis of thermoplastic material. These layers may besituated directly on top of each other or may be separated by one ormore intermediate layers, such as a glass fiber cloth or glass fiberfleece. According to this first possibility, the thickness of the panelpreferably is formed by these layers for 40 percent or more, or even forone-half or more thereof. In other words, the substrate of the panel,thus, the layers which are situated underneath the decor, substantiallycan be formed by such layers with thermoplastic material and individualfibers. It is evident that in this manner the extent of expansion orshrinkage with temperature variations can be reduced in an expedientmanner.

According to a second possibility, the panel comprises only one suchlayer on the basis of thermoplastic material and fibers. Such layerpreferably is situated at least in the middle of the thickness of thepanel and/or the substrate. The respective layer preferably forms atleast, 10 percent and still better at least 50 percent of the thicknessof the panel and/or the substrate. The remainder of the thickness of thesubstrate then can be formed by layers of thermoplastic material, whichthen do not necessarily comprise fibers, and/or by one or more glassfiber cloths or glass fiber fleeces. It is not excluded that therespective layer forms more than 80 percent or even the entiresubstrate.

Preferably, the substrate has a thickness of 1.3 to 10 millimeters. Theentire floor panel preferably has a thickness situated between 2 and 6millimeters. Preferably, the substrate forms at least one half of thethickness of the floor panel.

On the underside of the substrate, a counter layer or underlay can beprovided, preferably a vapor-tight layer. Such counter layer or underlaypreferably consists of a thermoplastic synthetic material layer. Thecounter layer preferably has a thickness which corresponds to thethickness of the top layer, including a possible backing layer, however,preferably is made thinner. The counter layer preferably functions as abalancing layer, such that a balanced sandwich structure can beobtained, namely without or only with minimal warping of the panels.

Preferably, said thermoplastic material of the layer which, according tothe invention, comprises the individual fibers, further also comprisesfillers, such as limestone.

A lacquer layer can be applied as the uppermost layer of the panel.Herein, this may relate to a UV- or electron beam-hardening lacquerlayer or to a PU lacquer layer.

Preferably, the invention is applied with floor panels which, at therespective edges, are provided with mechanical coupling means allowingto couple two of such floor panels to each other in such a manner that alocking is created in a vertical direction perpendicular to the plane ofthe coupled panels, as well as in a horizontal direction perpendicularto the coupled edge and in the plane of the panels. Preferably, thecoupling means also show one or a combination of two or more of thefollowing features:

-   -   the feature that the mechanical coupling means or coupling parts        are substantially realized as a tongue and a groove bordered by        an upper lip and a lower lip, wherein this tongue and groove        substantially are responsible for the locking in said vertical        direction, and wherein the tongue and the groove are provided        with additional locking parts, substantially responsible for the        locking in said horizontal direction. Preferably, the locking        parts comprise a protrusion on the lower side of the tongue and        a recess in the lowermost groove lip. Such coupling means and        locking parts are known, for example, from WO 97/47834;    -   the feature that the mechanical coupling means or coupling parts        press the coupled floor panels against each other, for example,        in that these mechanical coupling means are provided with a        so-called pre-tension, as known as such from EP 1 026 341. The        tensioning force with which the floor panels are pressed against        each other or towards each other, can be obtained, for example,        in combination with the above feature, by means of a lower lip,        which is bent out in coupled position and which, when trying to        spring back, presses against the lower side of the tongue;    -   the feature that the mechanical coupling means allow a coupling        by means of a horizontal, or quasi-horizontal shifting movement        of the panels towards each other;    -   the feature that the mechanical coupling means allow a coupling        by means of a turning movement W along the respective edges;    -   the feature that the mechanical coupling means allow a coupling        by means of a downward-directed movement of a male coupling part        having, for example, a tongue, up into a female coupling part        having, for example, a groove. With this type of panels, there        is a high risk that the connection will get released with an        expansion or pressing upward of the panels, as in such case the        locking in vertical direction can be weak;    -   the feature that the mechanical coupling means, or at least the        pertaining upper edge, are realized by means of a milling        operation with rotating milling tools.

Preferably, said coupling means substantially are realized in saidsubstrate, more particularly at least in the layer which, according tothe invention, comprises the loose fibers. Preferably, said couplingmeans are provided by means of a milling operation with rotating millingtools. Preferably, the floor panel of the invention relates to arectangular, either oblong or square, panel, which is provided withmechanical coupling means on both pairs of opposite edges.

Panels which are provided with coupling means preferably have athickness of at least 2.5, still better at least 3 millimeters. Due tothe presence of said individual fibers, it becomes possible to providereliable coupling means in panels of 4 millimeters or less, too. As theobtained panels have higher dimensional stability, the coupling meanswill be less strained and can be made smaller.

It is not excluded that the invention is applied for panels which arefree from coupling means at their edges, wherein these panels then areintended for being glued to the underlying surface with their lowerside. Such panels preferably have a thickness of less than 4millimeters, however, preferably of more than 1.5 millimeters.

The panels of the invention preferably have a width of 8 centimeters ormore. Particularly preferred dimensions are a width situated between 14and 22 centimeters and a length situated between 118 and 220centimeters. It is clear that this relates to panel-shaped elements andthus not to wall-to-wall floor covering. However, the panel-shapedelements do not necessarily have to be rigid, but can be rollable. Inparticular, the invention relates to so-called LVT (luxury vinyl tile)in plank format or in tile format.

When using individual E-glass fibers having a length of 3.2 millimetersin a soft PVC with 20 percent by weight of plasticizer, the inventorshave found, with a heating from 20° C. to 120° C., an expansion of only0.05%, whereas with a similar sample, without application of theindividual fibers, an expansion of 0.35% was found. With cooling,similar values, then, however, for shrinkage were noted.

According to an independent second aspect, the invention also relates toa method which can be applied for manufacturing panels with thecharacteristics of the first aspect or the preferred embodimentsthereof, however, which can also be applied more widely. To this aim,the invention relates to a method for manufacturing panels, wherein saidmethod comprises at least the step of forming a layer of thermoplasticmaterial, with the characteristic that the formed layer comprisesindividual fibers preferably having a length greater than 1 millimeter.

According to a particular preferred embodiment, said layer is formed onthe basis of a granulate of said thermoplastic material. Preferably, thegranules of this granulate consist for at least 50 percent by weight orfor 60 to 80 percent by weight of fillers, such as chalk. This granulatecan be, for example, initially strewn or otherwise deposited on anunderlying surface, after which this granulate is consolidated to athermoplastic layer by means of a, preferably heated, press treatment.According to the most preferred embodiment, the granulate is deposited,or possibly strewn, on a transport device and is guided between thebelts of a continuous pressing device, where consolidating is performedor at least is initiated. According to the present particular preferredembodiment, to this aim a device can be applied, such as the one knownfrom WO 2012/016916. Preferably, the granulate has an average particlesize of 1 to 3 millimeters, or of approximately 2 millimeters. Accordingto a particular embodiment, use is made of so-called micro granulate orgranulate of an average particle size of less than 1 millimeter, suchas, for example, with a granulate of approximately 800 micrometers. Itis possible to work with granulates of less than 350 micrometers, oreven, still better, of 100 micrometers or less than 100 micrometers.Such small granulates preferably are obtained otherwise than solely bybreaking down still larger particles, but rather by solidifying thethermoplastic material. Solidification then will be performed, forexample, by quenching (English: quenching) in a liquid. This particulartechnique for forming granulate leads to a more spherical shape of theparticles in the obtained granulate. By making use of granulates smallerthan 1 millimeter, or micro granulate, possibly obtained bysolidification, a more uniform composition of the respectivethermoplastic layer can be obtained. The individual fibers of theinvention will have an even better effect when they are situated in alayer on the basis of such granulate.

The individual fibers can also be strewn or be incorporated in thegranules of the strewn granulate.

The use of the above-mentioned micro granulate also has advantages whenthe final layer does not comprise any individual fibers. Therefore, theinvention, according to a particular independent aspect, also relates toa method for manufacturing panels, wherein this method comprises atleast the step of forming a layer of thermoplastic material, with thecharacteristic that said layer is formed on the basis of a strewngranulate of said thermoplastic material and that said granulate has anaverage particle size of less than 1 mm, and still better an averageparticle size of 350 micrometers or less, or 100 micrometers or less.Preferably, the average particle size is larger than 25 micrometers,such that caking of the granulate is prevented and good flow propertiesof the granulate are maintained. It is clear that such method haspreferred embodiments, which correspond to the preferred embodiments ofthe method of the second aspect, without the necessity of having toapply individual fibers. It is clear that preferably soft PVC is appliedas the thermoplastic material and that the respective thermoplasticlayer preferably further also comprises fillers, such as chalk or lime.These fillers may or may not be supplied via the respective granulate.Preferably, the granulate comprises more than 50 percent by weight offillers and still better between 60 and 80 percent by weight of fillers,for example, approximately 70 or 72 percent by weight. By applyinghighly filled granulate, a better distribution of the fillers in thelayer to be realized is obtained, as well as a smooth productionprocess. Further, it is clear that this method can be applied formanufacturing floor panels similar to those of the first aspect or thepreferred embodiments thereof, without the necessity of having to applythe individual fibers mentioned there.

According to another embodiment of the second aspect, said layer isformed on the basis of an extruded thermoplastic material. Herein, thismay relate, for example, to material obtained by means of a so-calledBanbury mixer (Kobe Steel Ltd.), in which granules of the respectivethermoplastic material are kneaded, wherein the kneaded material, forexample, at least between a set of rollers, is extruded to a layer.Herein, the risk is created that the fibers are broken down duringmixing.

Also according to the above two particular preferred embodiments, saidgranulates preferably comprise at least a portion of said individualfibers, preferably glass fibers.

It is evident that the layer obtained in the aforementioned step thenmust be processed together with other material, whether or not inlayers, for forming the final panel. It is also possible that in thefirst place plates or sheets are obtained, from which a plurality ofsuch panels is obtained by subdividing them.

Processing the respective layer generally can be performed in variousmanners. According to a first possibility, by means of heat and pressurethe respective layer, at least at the surface, is melted together withone or more further thermoplastic layers, such as a printed decor filmand/or a wear layer and/or a further substrate layer. According to asecond possibility, the material of one or more further layers, inparticular one or more further substrate layers, is provided in liquidform or in paste form by calendering it or providing it on the alreadyformed layer in another manner. According to a third possibility, thelayer, which according to the invention comprises the fibers, isprovided on already formed other layers, for example, on a glass fiberfleece or on a glass fiber cloth and/or on a further, already formedsubstrate layer.

Preferably, the method of the invention comprises the step of providinga glass fiber layer, preferably a glass fiber fleece or “non-woven”, inthe respective layer.

It is noted that the transparent wear layer, when applied, preferably isfree from fibers, such as glass fibers. When use is made of a decorfilm, this latter, too, preferably is free from such individual fibers.For the decor film, preferably a printed hard PVC film is applied,namely, a PVC film which is free or almost free from plasticizers. Theuse of a hard PVC film leads to a print of a higher quality, as it isless subject to dimensional changes during printing. This isparticularly advantageous when during printing one or more dryingtreatments by means of heat supply are performed, as may be the casewhen printing with water-based pigmented inks. For the transparent wearlayer, use can be made of a soft PVC layer, for example, with an amountof plasticizers of 12 percent by weight or more.

According to a third independent aspect, the present invention alsorelates to a material which can be applied in the method of the secondaspect and/or of the preferred embodiments thereof. To this aim, theinvention relates to a granulate for forming thermoplastic material,wherein this granulate, apart from the respective thermoplasticmaterial, also comprises glass fibers preferably having an averagelength greater than 1 mm, and still better having an average length of 3millimeters or more. Possibly, the granulate can comprise fillers, suchas lime or chalk. In such case, the granulate preferably comprises atleast 50 percent by weight or from 60 to 80 percent by weight offillers, such as chalk.

It is evident that the thermoplastic material further can have thecompositions stated in the context of the first aspect. Preferably, thethermoplastic material relates to a feedstock for forming semi-rigid orsoft PVC. Preferably, this PVC comprises an amount of plasticizer ofmore than 12 percent by weight, for example, of 20 percent by weight ormore.

It is clear that, according to the invention, by “substrate” an innerlayer of the floor panel itself is meant, which as such can be madesingle- or multi-layered, however, wherein the respective layer orlayers preferably have a common thickness which is larger than one halfof the thickness of the entire panel concerned and/or wherein therespective layer or layers have a common weight which preferably ishigher than one half of the weight of the entire panel concerned.Preferably, the contour of the possible coupling means is substantiallyor entirely realized in the substrate.

Further, it is clear that by “fibers”, elongate particles are meant.Preferably, the length of such fiber is at least hundred times theaverage diameter thereof. Preferably, this relates to fibers with acircular or approximately circular cross-section.

BRIEF DESCRIPTION OF THE DRAWINGS

With the intention of better showing the characteristics of theinvention, hereafter, as an example without any limitative character,some preferred embodiments are described, with reference to theaccompanying drawings, wherein:

FIG. 1 represents a panel with the characteristics of the invention;

FIG. 2, at a larger scale, represents a cross-section according to linesII-II in FIG. 1;

FIG. 3 schematically represents some steps in a method with thecharacteristics of the second aspect.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 represents a rectangular and oblong floor panel 1 with a pair oflong sides 2-3 and a pair of short sides 4-5.

FIG. 2 represents that the respective floor panel 1 is composed ofvarious layers 6-7-8-9-10.

The substrate 11 is formed by a layer 9 of thermoplastic material, inthis case soft PVC, which comprises individual fibers, such as glassfibers. The respective substrate layer 9 further comprises an embeddedglass fiber fleece 12. Above the respective layer 9, a top layer 13 isprovided, which as such comprises a printed decor film 7 and atransparent wear layer 6 on the basis of thermoplastic material. The toplayer 13 further also comprises a backing layer 8 located underneath thedecor film 7. In the example, the backing layer 8, the decor film 7 andthe wear layer 6 are made on the basis of polyvinyl chloride.Preferably, the decor film 7 is made as a printed hard PVC film, whereasthe wear layer 6 and possibly the optional backing layer 8 preferablyare realized on the basis of soft PVC, namely with an amount ofplasticizer of 12 percent by weight or more.

In the example, the decor film 7 is provided with a print with a woodpattern 14, wherein, per panel 1, each time the image of a single woodenboard is provided.

On the lower side 15 of the substrate 11, a counter layer 10 isprovided, which is also based on soft PVC.

FIG. 2 represents that the layer 9 comprising the fibers is present atleast in the middle of the thickness T of the substrate 11. In thiscase, the respective layer 9 forms the entire substrate 11.

FIG. 2 further also represents that the respective layer 9 comprisingthe individual fibers constitutes at least 40 percent and here even morethan one half of the thickness T of the panel 1.

Further, the panel 1 of the example is provided with mechanical couplingmeans or coupling parts 16 on both opposite edges 2-3. FIG. 2 shows thatat least the mechanical coupling means 16 on the long pair of edges 2-3allow that two of such floor panels 1 can be coupled to each other insuch a manner that a locking is created in a vertical direction V1perpendicular to the plane of the coupled panels 1, as well as in ahorizontal direction H1 perpendicular to the coupled edges 2-3 and inthe plane of the panels 1. The illustrated coupling means 16 show thecharacteristic that they are substantially realized as a tongue 17 and agroove 18 bordered by an upper lip 19 and a lower lip 20, wherein saidtongue 17 and groove 18 substantially are responsible for the locking insaid vertical direction V1, and wherein the tongue 17 and the groove 18are provided with additional locking parts 21-22 substantiallyresponsible for the locking in said horizontal direction H1. In thiscase, the locking parts comprise a protrusion 21 on the lower side ofthe tongue 17 and a cooperating-therewith recess 22 in the lower lip 20.

The coupling means 16 represented here allow at least a coupling bymeans of a turning movement W along the respective edges 2-3.

The mechanical coupling means 16 are substantially realized in the layer9, which, according to the invention, comprises the individual fibers.In the example, they are provided by means of a milling treatment, forexample, by means of rotating tools.

FIG. 3 represents some steps of a method for manufacturing the panel ofFIGS. 1 and 2. More particularly, the step is represented of forming thelayer 9 with thermoplastic material, which, according to the invention,comprises the individual fibers.

In the example of FIG. 3, the respective layer 9 is formed on the basisof a granulate 23 of the respective thermoplastic material. Herein, thisrelates to a granulate 23 with the characteristics of the third aspect,wherein the granules also comprise glass fibers.

FIG. 3 represents that the granulate 23 initially is deposited on atransport device 25 by means of a strewing device 24, after which it isconsolidated between the belts 26 of a continuous pressing device 17.Herein, the granulate 23 is transported along one or more heatingdevices 28 and possibly it can be cooled again after the press treatmentor at the end of the press treatment. By cooling, it is achieved thatthe pressed plates, sheets or layers relatively fast are manageable forfurther processing.

FIG. 3 further also represents that simultaneously with pressing, afurther layer, in this case the glass fiber layer 12, can be applied orinserted by providing it on or between the granulate 23 in the presstreatment. This may relate, for example, as aforementioned, to a glassfiber layer 12 or to a backing layer 8, a decor film 7 or a wear layer6. It may also relate to a composition of layers already laminatedtogether, such as an already entirely or partially composed top layer 3,which, for example, comprises at least a decor film 7 and a wear layer6, or at least a backing layer 8 and a decor film 7; or the backinglayer 8, decor film 7 as well as the wear layer 6. A possiblesuperficial lacquer layer preferably is provided after the presstreatment. This is not represented here. According to another, notrepresented possibility, at least a decor film 7 or a wear layer 6, orpossibly a combination of both, is provided after the granulate 23already has been pressed at least partially, preferably already has beenpressed at least to a coherent whole. In this last case, the alreadypressed layer on the basis of granulate preferably is ground before theremaining layers 6-7 are provided thereon. For providing the decor film7 and/or the wear layer 6, preferably again use is made of a continuouspressing device. Instead of a grinding treatment, it is also possible towork with levelling, for example, by means of a plastisol.

The present invention is in no way limited to the herein above-describedembodiments; on the contrary, such panels, methods and granulates can berealized according to various variants, without leaving the scope of thepresent invention. Moreover, the panels, instead of as floor panels, canalso be realized as wall panels or ceiling panels or even as furniturepanels.

The invention claimed is:
 1. A panel for forming a floor covering,wherein this panel comprises: a substrate layer having a thickness of1.3 to 10 millimeters, said substrate layer being substantially formedby one or more layers of thermoplastic material, wherein this panel,above said one or more layers of thermoplastic material, comprises atleast also a printed decor and a translucent or transparent wear-layer,with at least one said layers of thermoplastic material situated atleast halfway in the thickness of the panel, wherein said thermoplasticmaterial is chosen from the list consisting of polyvinyl chloride,polypropylene, polyethylene, and polyurethane, wherein each of said oneor more layers of thermoplastic material also comprises at leastindividual glass fibers having a length greater than 1 millimeter, andwherein said individual glass fibers are loose and freely distributedwithin each of said layers of thermoplastic material, and wherein saidpanel at one or more edges comprises mechanical coupling parts allowingto couple two of such panels to each other; said coupling parts beingsubstantially realized in said substrate layer.
 2. The panel of claim 1,wherein said individual glass fibers are provided with a coating or atreatment which improves the adherence to the thermoplastic material. 3.The panel of claim 1, wherein said layer of thermoplastic material alsocomprises at least a glass fiber cloth or glass fiber fleece.
 4. Thepanel of claim 1, wherein this panel comprises at least two such layerson the basis of thermoplastic material.
 5. The panel of claim 1, whereinsaid thermoplastic material relates to soft polyvinyl chloride with apercentage of plasticizer of 12 percent by weight or more.
 6. The panelof claim 1, wherein said thermoplastic material further also comprisesfillers.
 7. The panel of claim 1, wherein said individual glass fiberson average have a diameter situated between 5 and 25 micrometers.
 8. Thepanel of claim 1, wherein said individual fibers have an average lengthof more than 3 mm.
 9. A panel for forming a floor covering, wherein thispanel comprises: a substrate having a thickness of 1.3 to 10millimeters, said substrate being substantially formed by one or morelayers of thermoplastic material, wherein this panel, above said one ormore layers of thermoplastic material, comprises at least also a printeddecor and a translucent or transparent wear-layer, with at least onesaid layers of thermoplastic material situated at least halfway in thethickness of the panel, wherein said thermoplastic material is chosenfrom the list consisting of polyvinyl chloride, polypropylene,polyethylene, and polyurethane, wherein each of said one or more layersof thermoplastic material also comprises at least individual glassfibers having a length greater than 1 millimeter, and wherein saidindividual glass fibers are loose and freely distributed within each ofsaid layers of thermoplastic material, wherein said panel at one or moreedges comprises mechanical coupling parts allowing to couple two of suchpanels to each other; said coupling parts being substantially realizedin said substrate, and wherein said wear-layer has a thickness of 0.2 to0.4 millimeters.
 10. A method for manufacturing panels, wherein saidmethod comprises at least the step of: providing a substrate having athickness of 1.3 to 10 millimeters by at least forming one or morelayers of thermoplastic material on the basis of a strewn granulate ofsaid thermoplastic material, wherein said one or more layers ofthermoplastic material is situated at least halfway in the thickness ofthe panel, wherein said thermoplastic material is chosen from the listconsisting of polyvinyl chloride, polypropylene, polyethylene, andpolyurethane, wherein each of the formed one or more layers comprisesindividual fibers having a length greater than 1 mm, wherein saidindividual glass fibers are loose and freely distributed within each ofsaid layers of thermoplastic material, and forming a printed décor and atranslucent or transparent wear layer above said layer of thermoplasticmaterial, and wherein at one or more edges of said panel, mechanicalcoupling parts are formed allowing to couple two of such panels to eachother, said coupling parts being substantially realized in saidsubstrate layer.
 11. The method of claim 10, wherein said strewn layeris consolidated between the belts of a continuous press device.
 12. Themethod of claim 11, wherein said granulates comprise at least a portionof said individual glass fibers.
 13. The method of claim 10, whereinsaid thermoplastic material relates to soft PVC and wherein saidindividual fibers are provided with a coating or a treatment whichimproves the adherence to the thermoplastic material.
 14. The methodaccording to claim 10, wherein the aforementioned granulate has anaverage particle size of less than 1 mm.
 15. The method of claim 14,wherein for the granulate, it is started from a granulate with anaverage particle size of 350 micrometers or less.
 16. The methodaccording to claim 10, wherein said granulate, apart from saidthermoplastic material, also comprises glass fibers having a lengthgreater than 1 mm.